Homocystinuria presenting as psychosis in an adolescent

Obsessive-Compulsive Symptoms as a Manifestation of Homocystinuria

Homocystinuria is a rare autosomal recessive metabolic disorder due to a defect in the cystathionine β-synthase (CBS) that leads to high homocysteine plasma levels. Psychiatric symptoms secondary to homocystinuria have been described in the literature; however, there is a lack of information about obsessive-compulsive symptoms correlated to this disorder. We describe the case of a 39 years old man, diagnosed with homocystinuria in childhood, with no previous psychiatric history that presented obsessive-compulsive disorder (OCD) like symptoms, as a manifestation of homocystinuria. This case underlines the importance for a psychiatrist to explore medical nonpsychiatric history, especially when presentation is abrupt, atypical, or in treatment-resistant cases.

The psychopharmacology of Wilson disease and other metabolic disorders

Wilson disease (WD) is a hereditary metabolic disorder (HMD) caused by a mutation in the copper-transporting gene ATP7B affecting the liver and central nervous system. About 30% of patients with WD may initially present with psychiatric symptoms, and management can be difficult. More generally, HMDs are a rare but important cause of psychiatric disorders in adolescents and adults. Main signs of HMDs may remain isolated for years before the appearance of hepatic or neurologic signs. The incidence of HMDs has been estimated at approximately 40 cases per 100,000 live births. Some of them are treatable and new diagnostic methods and therapies have become available. HMDs that present purely with psychiatric symptoms are very difficult to diagnose due to low awareness of these rare diseases among psychiatrists and neurologists. However, it is important to identify HMDs in order to provide disease-specific treatment and possible prevention of irreversible physical and neurologic complications. Genetic counseling can also be provided. Psychotropic medications should be prescribed carefully in that indication. This chapter focuses on three HMD categories: chronic, treatable HMDs (e.g., WD); acute, treatable HMDs; and chronic HMDs that are difficult to treat. In this review we focus on the psychopharmacology of WD and other chronic and difficult-to-treat HMDs. We provide some keys to take into account the main side effects associated with common psychotropic medications.

Homocystinuria with Stroke and Positive Familial History

Homocystinuria is the second most common treatable aminoacidopathy. Clinically, affected patients present with eye, skeleton, central nervous system, and most importantly, vascular system abnormalities. This autosomal recessive disorder leads to accumulation of homocysteine and its metabolites in the blood and urine. In this report, we present a case with clinical and biochemical findings of homocystinuria with stroke and a positive familial history of the disease in her brother. A 4-year-old girl was admitted to pediatric emergency ward because of acute onset of right hemiparesis and subsequent generalized tonic–clonic seizures. Cranial magnetic resonance imaging revealed acute infarct areas in the left cerebral hemisphere. Metabolic screening revealed elevated concentrations of serum homocysteine and methionine and a normal serum concentration of vitamin B12. These findings, along with a positive familial history led to the diagnosis of homocystinuria. In any child who presents with stroke, some rare condition such as homocystinuria should be considered in diagnosis.

Acute psychosis in an adolescent with undiagnosed homocystinuria

Homocystinuria due to cystathionine-β-synthase deficiency (CBS deficiency) usually presents with ectopia lentis, myopia, intellectual disability, skeletal anomalies resembling Marfan syndrome, and thromboembolic events. Whereas neurodevelopment impairments have been often described in untreated homocystinuria adult patients, acute psychosis has rarely been reported as a presenting symptom of the disease. Here, we describe a 17-year-old girl affected by CBS deficiency presenting acute onset of visual hallucinations, behavioral perseverance, psychomotor hyperactivity, and affective inappropriateness. Ectopia lentis, diagnosed several years before, didn't have been considered as possible sign of a metabolic disorder. Psychotic symptoms were unresponsive to the conventional antipsychotic drugs and relieved after pyridoxine and folic acid treatment.

CONCLUSION

A diagnosis of homocystinuria due to CBS deficiency should be considered in patients presenting, as target signs, ectopia lentis with or without learning difficulties, and should also be taken into account as a potentially treatable cause of acute psychosis in childhood and adolescence.

WHAT IS KNOWN

• Homocystinuria frequently present with ectopia lentis, myopia, cognitive impairment, Marfan-like phenotype, osteoporosis, cerebrovascular, or cardiac thrombosis. • Acute psychosis has rarely been reported as a presenting symptom of the disease.

WHAT IS NEW

• The complete psychotic symptoms' remission with pharmacological doses of pyridoxine and folic acid, without antipsychotic drugs.

Psychiatric manifestations of treatable hereditary metabolic disorders in adults

Detecting psychiatric disorders of secondary origin is a crucial concern for the psychiatrist. But how can this reliably be done among a large number of conditions, most of which have a very low prevalence? Metabolic screening undertaken in a population of subjects with psychosis demonstrated the presence of treatable metabolic disorders in a significant number of cases. The nature of the symptoms that should alert the clinician is also a fundamental issue and is not limited to psychosis. Hereditary metabolic disorders (HMD) are a rare but important cause of psychiatric disorders in adolescents and adults, the signs of which may remain isolated for years before other more specific organic signs appear. HMDs that present purely with psychiatric symptoms are very difficult to diagnose due to low awareness of these rare diseases among psychiatrists. However, it is important to identify HMDs in order to refer patients to specialist centres for appropriate management, disease-specific treatment and possible prevention of irreversible physical and neurological complications. Genetic counselling can also be provided. This review focuses on three HMD categories: acute, treatable HMDs (urea cycle abnormalities, remethylation disorders, acute intermittent porphyria); chronic, treatable HMDs (Wilson's disease, Niemann-Pick disease type C, homocystinuria due to cystathionine beta-synthase deficiency, cerebrotendinous xanthomatosis); and chronic HMDs that are difficult to treat (lysosomal storage diseases, X-linked adrenoleukodystrophy, creatine deficiency syndrome). We also propose an algorithm for the diagnosis of HMDs in patients with psychiatric symptoms.

A forgotten lethal psychosis: a case report

Homocystinuria due to cystathionine β-synthase deficiency is an inborn error of metabolism first described almost 50 years ago, which involves the accumulation of plasma homocysteine and other metabolites. Without early detection and appropriate treatment, common and sometimes lethal consequences include ocular abnormalities, osteoporosis, developmental delays, marfanoid phenotype, vascular disease, and mental retardation. Almost 50% of subjects develop a psychiatric disorder during their life, but only 2.8% present a psychiatric symptom as the initial manifestation. Among this group, psychotic disorders are infrequent. We describe the case of a 17-year-old boy presenting with a first episode psychosis and an unknown homocystinuria due to cystathionine β-synthase deficiency, which led to a lethal outcome.

Dietary practices in pyridoxine non-responsive homocystinuria: a European survey

BACKGROUND

Within Europe, the management of pyridoxine (B6) non-responsive homocystinuria (HCU) may vary but there is limited knowledge about treatment practice.

AIM

A comparison of dietetic management practices of patients with B6 non-responsive HCU in European centres.

METHODS

A cross-sectional audit by questionnaire was completed by 29 inherited metabolic disorder (IMD) centres: (14 UK, 5 Germany, 3 Netherlands, 2 Switzerland, 2 Portugal, 1 France, 1 Norway, 1 Belgium).

RESULTS

181 patients (73% >16 years of age) with HCU were identified. The majority (66%; n=119) were on dietary treatment (1-10 years, 90%; 11-16 years, 82%; and >16 years, 58%) with or without betaine and 34% (n=62) were on betaine alone. The median natural protein intake (g/day) on diet only was, by age: 1-10 years, 12 g; 11-16 years, 11 g; and >16 years, 45 g. With diet and betaine, median natural protein intake (g/day) by age was: 1-10 years, 13 g; 11-16 years, 20 g; and >16 years, 38 g. Fifty-two percent (n=15) of centres allocated natural protein by calculating methionine rather than a protein exchange system. A methionine-free l-amino acid supplement was prescribed for 86% of diet treated patients. Fifty-two percent of centres recommended cystine supplements for low plasma concentrations. Target treatment concentrations for homocystine/homocysteine (free/total) and frequency of biochemical monitoring varied.

CONCLUSION

In B6 non-responsive HCU the prescription of dietary restriction by IMD centres declined with age, potentially associated with poor adherence in older patients. Inconsistencies in biochemical monitoring and treatment indicate the need for international consensus guidelines.

Congenital and acquired disorders presenting as psychosis in children and young adults

A review of the published literature found 60 congenital and acquired disorders with symptoms that include psychosis in youth. The prevalence, workup, genetics, and associated neuropsychiatric features of each disorder are described. Eighteen disorders (30%) have distinct phenotypes (doorway diagnoses); 18 disorders (30%) are associated with intellectual disability; and 43 disorders (72%) have prominent neurologic signs. Thirty-one disorders (52%) can present without such distinct characteristics, and are thus more easily overlooked. A systematic and cost-effective differential diagnostic approach based on estimated prevalence and most prominent associated signs is recommended.

The neuropsychiatry of inborn errors of metabolism

A number of metabolic disorders that affect the central nervous system can present in childhood, adolescence or adulthood as a phenocopy of a major psychiatric syndrome such as psychosis, depression, anxiety or mania. An understanding and awareness of secondary syndromes in metabolic disorders is of great importance as it can lead to the early diagnosis of such disorders. Many of these metabolic disorders are progressive and may have illness-modifying treatments available. Earlier diagnosis may prevent or delay damage to the central nervous system and allow for the institution of appropriate treatment and family and genetic counselling. Metabolic disorders appear to result in neuropsychiatric illness either through disruption of late neurodevelopmental processes (metachromatic leukodystrophy, adrenoleukodystrophy, GM2 gangliosidosis, Niemann-Pick type C, cerebrotendinous xanthomatosis, neuronal ceroid lipofuscinosis, and alpha mannosidosis) or via chronic or acute disruption of excitatory/inhibitory or monoaminergic neurotransmitter systems (acute intermittent porphyria, maple syrup urine disease, urea cycle disorders, phenylketonuria and disorders of homocysteine metabolism). In this manuscript we review the evidence for neuropsychiatric illness in major metabolic disorders and discuss the possible models for how these disorders result in psychiatric symptoms. Treatment considerations are discussed, including treatment resistance, the increased propensity for side-effects and the possibility of some treatments worsening the underlying disorder.

[Psychiatric and cognitive signs associated with inborn errors of metabolism]

BACKGROUND

Inborn errors of metabolism are rare disease and forms with presenting psychiatric signs are even rarer. However, some of them are treatable and early treatment (which may start when psychiatric signs are the only manifestation) may lead to more efficacy and better improvement for either psychiatric and organic signs. Recognition by psychiatrist, and non-specialized practionners, is therefore a major issue for patients and health care.

OBSERVATION

After an illustrating case report, we propose a short description of psychiatric signs, focusing on presenting signs, associated with neurometabolic disease. We also propose a pragmatic and simple clinical diagnostic strategy for practionners when facing to atypical psychiatric signs leading to a minimum reasonable exploratory assessment.

CONCLUSION

Atypical psychiatric signs must be known by psychiatrists in order to seek neurometabolic disease. Multidisciplinary approach, especially between psychiatrists and neurologists, is crucial in this topic.

Stroke in early childhood due to homocystinuria

A previously healthy girl, age 3 years 9 months, presented with right-sided hemiparesis and seizures. Ischemic infarction was confirmed through magnetic resonance imaging and magnetic resonance angiography. Extensive evaluation to discover the underlying etiologies and risk factors predisposing this patient to stroke included coagulation defects, cardiac anomalies, congenital inborn metabolism deficiency, and infections and trauma. Based on the clinical and laboratory results, a diagnosis of homocystinuria was made. Homocystinuria is an inherited disorder that affects the metabolism of the amino acid methionine. Although homocystinuria is usually associated with ischemic strokes, the sudden onset of stroke as the initial clinical presentation of homocystinuria is very rare in early childhood. Based on this case, however, metabolic screening for hyperhomocystinemia is recommended in any child presenting with a stroke.

[Treatable hereditary neuro-metabolic diseases]

Hereditary metabolic diseases may appear during adolescence or young adulthood, revealed by an apparently unexplained neurological or psychiatric disorder. Certain metabolic diseases respond to specific treatments and should be identified early, particularly in emergency situations where rapid introduction of a treatment can avoid fatal outcome or irreversible neurological damage. The main diseases leading to an acute neurological syndrome in the adult are urea cycle disorders, homocysteine metabolisms disorders and porphyria. More rarely, Wilson's disease, aminoacid diseases, organic aciduria, or pyruvate dehydrogenase deficiency, beta-oxidation disordes or biotin metabolism may be involved. Most emergency situations can be screen correctly with simple tests (serum ammonia, homocysteine, lactate, urinary prophyrines, acylcarnitine pattern, amino acid and organic acid chromatography). For chronic situations, the main treatable diseases are Wilson's disease, homocysteine, cerebrotendinous xanthomatosis, Refsum's disease, vitamin E deficiency, Gaucher's disease, Fabry's disease, and neurotransmitter metabolism disorders. We present treatable metabolic disorders as a function of the different clinical situations observed in adults.

Psychiatric manifestations revealing inborn errors of metabolism in adolescents and adults

Inborn errors of metabolism (IEMs) may present in adolescence or adulthood as a psychiatric disorder. In some instances, an IEM is suspected because of informative family history or because psychiatric symptoms form part of a more diffuse clinical picture with systemic, cognitive or motor neurological signs. However, in some cases, psychiatric signs may be apparently isolated. We propose a schematic classification of IEMs into three groups according to the type of psychiatric signs at onset. Group 1 represents emergencies, in which disorders can present with acute and recurrent attacks of confusion, sometimes misdiagnosed as acute psychosis. Diseases in this group include urea cycle defects, homocysteine remethylation defects and porphyrias. Group 2 includes diseases with chronic psychiatric symptoms arising in adolescence or adulthood. Catatonia, visual hallucinations, and aggravation with treatments are often observed. This group includes homocystinurias, Wilson disease, adrenoleukodystrophy and some lysosomal disorders. Group 3 is characterized by mild mental retardation and late-onset behavioural or personality changes. This includes homocystinurias, cerebrotendinous xanthomatosis, nonketotic hyperglycinaemia, monoamine oxidase A deficiency, succinic semialdehyde dehydrogenase deficiency, creatine transporter deficiency, and alpha and beta mannosidosis. Because specific treatments should be more effective at the 'psychiatric stage' before the occurrence of irreversible neurological lesions, clinicians should be aware of atypical psychiatric symptoms or subtle organic signs that are suggestive of an IEM. Here we present an overview of IEMs potentially revealed by psychiatric problems in adolescence or adulthood and provide a diagnostic strategy to guide metabolic investigations.

Therapy insight: inborn errors of metabolism in adult neurology--a clinical approach focused on treatable diseases

Inborn errors of metabolism (IEMs) are genetic disorders characterized by dysfunction of an enzyme or other protein involved in cellular metabolism. In most cases, IEMs involve the nervous system. The first clinical symptoms of IEMs usually present in infancy, but in an unknown proportion of cases they can appear in adolescence or adulthood. In this Review, we focus on treatable IEMs, presenting acutely or chronically, that can be diagnosed in an adult neurology department. To make our presentation readily usable by clinicians, the Review is subdivided into eight sections according to the main clinical presentations: emergencies (acute encephalopathies and strokes), movement disorders, peripheral neuropathies, spastic paraparesis, cerebellar ataxia, psychiatric disorders, epilepsy and leukoencephalopathies. Our aim is to present simple guidelines to enable neurologists to avoid overlooking a treatable metabolic disease.

Do maternal folate and homocysteine levels play a role in neurodevelopmental processes that increase risk for schizophrenia?

OBJECTIVE

Evidence from many different lines of research supports the hypothesis that schizophrenia is a disorder of development with etiological factors implicated as early as the second trimester in utero. We suggest that low maternal folate, acting to increase homocysteine levels, may provide a functional link between many of the identified prenatal risk factors and the hypothesized mechanisms whereby neurodevelopmental patterning deviates toward a schizophrenic potential.

METHODS

PubMed was searched from the present back to 1963, when elevated homocysteine was identified as a pathogen in homocystinuria as first described by Carson and colleagues (Arch Dis Child 1963;38:425-36). All articles for homocystinuria, homocysteine, folate, and development with schizophrenia were evaluated.

RESULTS

The findings from this review support the hypothesis that maternal low folate and high homocysteine levels may provide a potential teratogenic mechanism that increases the risk for developing schizophrenia.

CONCLUSION

The potential role of maternal folate deficiency and hyperhomocystinemia in the genesis of schizophrenia would extend the range of their known teratogenic effects. Given the potential for preventive treatment offered by this hypothesis, we believe further investigation into this mechanism is warranted.

Ungew�hnlicher Verlauf einer ?-Mannosidose mit Symptomen einer paranoid-halluzinatorischen Psychose

We report the case of a 27-year-old female with recurrent paranoid-hallucinatory episodes who was initially diagnosed as suffering from schizophrenic psychosis. After 10 years of treatment under this diagnosis, alpha-mannosidosis was identified to be the underlying cause of her psychiatric symptoms. alpha-Mannosidosis is a rare autosomal recessive lysosomal storage disorder associated with decreased activity of the enzyme mannosidase. In the present case, diagnosis was made late in the illness after failure of a response to antipsychotic treatment and with the patient additionally showing progressive cognitive decline. Only after extensive investigation was the diagnosis made by showing decreased alpha-mannosidase enzyme activity in serum and blood leukocytes. This case demonstrates that an unusual clinical course or striking symptom patterns, especially in association with somatic comorbidity, in psychotic patients should lead to diagnostic consideration of inherited metabolic disease.